Devices and methods for fixation of animal tissue

Abstract

This document relates to tissue modification and, more particularly, to modification of biological tissue for implantation in a mammal. For example, this document relates to tissue tensioning devices and methods used during fixation of tissues for bioprosthetic heart valves.

What is claimed is: 
     
         1 . A tissue tensioning apparatus for tensioning a tissue, the apparatus comprising:
 a peripheral frame defining an interior space;   a plurality of elongate tensioning members each including a tissue attachment member configured to attach to the tissue, each of the plurality of tensioning members being attachable to the frame such that the tissue attachment member is disposed within the interior space; and   a frame size adjustment feature coupled to the frame and arranged to adjust a configuration of the frame and positions of the tissue attachment members relative to the interior space when the plurality of tensioning members are attached to the frame such that the tissue attachment members are disposed within the interior space.   
     
     
         2 . The apparatus of  claim 1 , wherein the interior space is circular. 
     
     
         3 . The apparatus of  claim 1 , wherein the interior space is generally triangular. 
     
     
         4 . The apparatus of  claim 1 , wherein the interior space is polygonal. 
     
     
         5 . The apparatus of  claim 1 , wherein the tissue attachment member comprises a clip. 
     
     
         6 . The apparatus of  claim 1 , wherein the tissue attachment member comprises a hook. 
     
     
         7 . The apparatus of  claim 1 , wherein the frame size adjustment feature comprises a rotatable screw or worm gear that meshes with features on the frame. 
     
     
         8 . The apparatus of  claim 1 , wherein the frame size adjustment feature comprises an inflatable balloon member. 
     
     
         9 . The apparatus of  claim 1 , wherein the frame size adjustment feature comprises a pivot arm. 
     
     
         10 . The apparatus of  claim 1 , wherein the frame size adjustment feature is configured to bi-axially adjust the positions of the tissue attachment members relative to the interior space. 
     
     
         11 . The apparatus of  claim 1 , wherein the frame size adjustment feature is configured to adjust the positions of the tissue attachment members relative to the interior space in four or more different directions. 
     
     
         12 . The apparatus of  claim 1 , wherein the frame size adjustment feature is configured to adjust the positions of the tissue attachment members relative to the interior space in eight or more different directions. 
     
     
         13 . The apparatus of  claim 1 , wherein the frame size adjustment feature is configured to adjust the positions of the tissue attachment members relative to the interior space in twelve or more different directions. 
     
     
         14 . The apparatus of  claim 1 , wherein the frame includes a plurality attachment features whereby the plurality of elongate tensioning members are attachable to the frame. 
     
     
         15 . The apparatus of  claim 14 , wherein the plurality attachment features comprise slots. 
     
     
         16 . The apparatus of  claim 14 , wherein the plurality attachment features comprise clamps. 
     
     
         17 . A method for tissue modification, the method comprising:
 attaching a tissue to a tissue tensioning apparatus, the tissue tensioning apparatus comprising:
 a peripheral frame defining an interior space; 
 a plurality of elongate tensioning members each including a tissue attachment member configured to attach to the tissue, each of the plurality of tensioning members being attachable to the frame such that the tissue attachment member is disposed within the interior space; and 
 a frame size adjustment feature coupled to the frame and arranged to adjust a configuration of the frame and positions of the tissue attachment members relative to the interior space when the plurality of tensioning members are attached to the frame such that the tissue attachment members are disposed within the interior space; and 
   adjusting the frame size adjustment feature to apply tension to the tissue.   
     
     
         18 . The method of  claim 17 , wherein an entirety of the tissue is within the interior space when the tissue is attached to the tissue tensioning apparatus. 
     
     
         19 . The method of  claim 17 , further comprising applying a fixative to the tissue, wherein the fixative comprises glutaraldehyde. 
     
     
         20 . The method of  claim 17 , wherein the tension applied to the tissue is about 0.1 N to about 2 N, or wherein a tensile stress applied to the tissue by the tension is about 0.01 N/mm 2  to about 2 N/mm 2 .